Rapid readout of terahertz orbital angular momentum beams using atom-based imaging

TL;DR

This paper presents a fast, atom-based imaging method for reading out terahertz orbital angular momentum beams, enabling high-fidelity, rapid detection of beam modes for potential use in communications and microscopy.

Contribution

The authors introduce a novel atomic-vapour based technique for rapid, high-fidelity readout of terahertz OAM beams, including mode sign and magnitude detection.

Findings

Achieved 10 ms readout time for OAM modes.

Successfully imaged both azimuthal and radial indices.

Demonstrated reliable detection of low-intensity beams.

Abstract

We demonstrate the rapid readout of terahertz (THz) orbital angular momentum (OAM) beams using an atomic-vapour based imaging technique. OAM modes with both azimuthal and radial indices are created using phase-only transmission plates. The beams undergo terahertz to optical conversion in an atomic vapour, before being imaged in the far field using an optical CCD camera. In addition to the spatial intensity profile, we also observe the self-interferogram of the beams by imaging through a tilted lens, allowing the sign and magnitude of the azimuthal index to be read out directly. Using this technique, we can reliably read out the OAM mode of low-intensity beams with high fidelity in 10 ms. Such a demonstration is expected to have far-reaching consequences for proposed applications of terahertz OAM beams in communications and microscopy.